How to build an Epower system

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Re: How to build an Epower system

PostPosted: Sun Nov 10, 2013 2:49 pm

sirzepp wrote:The 20C draw rule of thumb is one I've never heard. Now I get why my expensive Hyperion 45C 2200mah packs are puffing in my little EDF despite the fact that I am under 45C on draw and always land with ~20% in the pack...I know I'm over 20C draw on these packs. I can't go to a bigger pack in this little jet...so my only other option is spend more cash on a TP pack I guess. I've got three of the hyperions...at 90 bucks a piece...and they come down a bit puffed every flight. Internal resistance is good...they are all around 15mOhm...the packs aren't much more than warm after a flight...but still they puff. It must be due to the higher than 20C amp draw because I upgraded to a 4400kv motor (don's RC Wicked EDF motor) and a 60 Amp ESC. Since the system is pulling full amps even at low throttle...this would explain why my packs are puffing, right?

Either that or the packs can't get rid of heat. Ventilation? Are they getting extra heat from the ESC?
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Re: How to build an Epower system

PostPosted: Sun Nov 10, 2013 3:24 pm

TriFlyer3D wrote: This is for the Bros starting out on Epower so I do not want to get too technical.



I think that the way you approached the subject is perfect!

Just follow the KV recommendations from Ron's post and you won't be disappointed.
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Re: How to build an Epower system

PostPosted: Sun Nov 10, 2013 5:24 pm

ThumbSkull wrote:
sirzepp wrote:The 20C draw rule of thumb is one I've never heard. Now I get why my expensive Hyperion 45C 2200mah packs are puffing in my little EDF despite the fact that I am under 45C on draw and always land with ~20% in the pack...I know I'm over 20C draw on these packs. I can't go to a bigger pack in this little jet...so my only other option is spend more cash on a TP pack I guess. I've got three of the hyperions...at 90 bucks a piece...and they come down a bit puffed every flight. Internal resistance is good...they are all around 15mOhm...the packs aren't much more than warm after a flight...but still they puff. It must be due to the higher than 20C amp draw because I upgraded to a 4400kv motor (don's RC Wicked EDF motor) and a 60 Amp ESC. Since the system is pulling full amps even at low throttle...this would explain why my packs are puffing, right?

Either that or the packs can't get rid of heat. Ventilation? Are they getting extra heat from the ESC?


Great point...I'm going to open the intake on the nose up a bit and see if it helps. It's pretty tight in there...(that's what he said).
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Re: How to build an Epower system

PostPosted: Thu Aug 20, 2015 2:04 pm

Bookmarked. Great info. This definitely help me start to learn how to setup a system.
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Re: How to build an Epower system

PostPosted: Mon May 29, 2017 3:03 pm

TriFlyer3D wrote:You can use the above to calculate an E power system for any plane as long as you have a good idea of what its flying weight will be. For example a 60 size plane is about 6 lbs so;
6 lbs x 225 Watts = 1350 Watts
1350 Watts / 22.2 (6S) = 60 amps
60 amps / 20C x 1000 = 3000 Mah.
1350 Watts / 125 = 10.8 oz.

6 lb plane using a 6S system = 1350 Watts needed, 60 amps required, minimum of 3000 Mah batteries and an 11 oz motor.

A note about controllers, always size your controller at least 10% higher than the calculations say is needed. In our 40 and 60 size examples that need 60 amps, a 70 amp controller would be minimum but an 80 amp would be better and it is a more popular size.
I

I'm going to pull the Saito 100 off of my Mojo 60 and go E. The above calculations fit this plane perfectly. I have decided to go with a Motrolfly 4315-500KV. I did a search and noticed that this motor was used successfully on a lot of Mojo 60's. Although Gus recommends 550KV special wind due to Zam needing more power on his Stix 60. But the Stix 60 is a pound heavier than the Mojo 60, so I am assuming that 500KV at my elevation with a 16X6 to 16X8 prop would be good.

I'm running this identical system on a GBR 50 with a 15X6 prop and it is great, although I am using 3S 3300 packs in series. I'm hoping that my 3300's will be sufficient on the 60 too :? Short flight times don't bother me..
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Re: How to build an Epower system

PostPosted: Mon May 29, 2017 3:09 pm

You should be fine , I run that power level in my EF edge and get about 6 min of flight with 3300 packs. It's about 5.75 lb though
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Re: How to build an Epower system

PostPosted: Mon May 29, 2017 3:12 pm

You'll like it better at 530-550.
I've had 500kV, took too big of a prop and honestly the MoAss just lumbers with a too large prop.
I have a 530kV and it is a good choice. I'm using 580kV on my 50 size and getting great power and flight times near 7 minutes.
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Re: How to build an Epower system

PostPosted: Mon May 29, 2017 3:26 pm

I still don't know how you run a 580, a 15x7 on my 580 kv pushes 100 amps, and I checked the kv thinking it might be high but it's 584, just about as close as you can get.

If I remember right I went to a 14x 6 and still did about 65/70 amps

If I was buying a new 4315 for a mojo if probably get a 530kv and run a 15x7, should do a comfertable 1500 watts run super cool and good flight times
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Re: How to build an Epower system

PostPosted: Mon May 29, 2017 3:37 pm

A. I'm rarely at full throttle.
B. It's on a Talon 90 so it might be current limiting but I can't feel it. There is no data log to check.
C. Stuff comes down at ballsack temps so I'm not worried.
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Re: How to build an Epower system

PostPosted: Mon May 29, 2017 3:41 pm

Obviously your not hammering it, and with the graphenes you use it could handle it if you did.

I guess the real question is why :)
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Re: How to build an Epower system

PostPosted: Mon May 29, 2017 3:51 pm

Efficiency.
I'm getting great flight times. Even hitting it pretty hard, I'm over 6 minutes.
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Re: How to build an Epower system

PostPosted: Mon May 29, 2017 3:58 pm

But it could be more efficient :)

I get it, I have one too, if I was buying one specifically for the M60 I'd probably get a 530 and run a 15x7, or the same prop on the 500 knowing I could prop up to a 16 on a different plane down the road.

But im more of a 4stroke feel guy
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Re: How to build an Epower system

PostPosted: Mon May 29, 2017 9:15 pm

ThumbSkull wrote:I have a 530kV and it is a good choice.


Dan and Mike, I appreciate those comments :tu: :tu:

Mike, on the 530KV, what prop do you like?

On my 500KV 3300's I get 5 1/2 minutes flight times with the 15X6 - which is about all my attention span is good for.. :wack: :nerd:
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Re: How to build an Epower system

PostPosted: Mon May 29, 2017 10:12 pm

Straightup wrote:
ThumbSkull wrote:I have a 530kV and it is a good choice.


Dan and Mike, I appreciate those comments :tu: :tu:

Mike, on the 530KV, what prop do you like?

On my 500KV 3300's I get 5 1/2 minutes flight times with the 15X6 - which is about all my attention span is good for.. :wack: :nerd:

You'll get less than that on a 6lb bird with 3300's. I run 4000 on my MoAss and get a solid 6 minutes. That one is in storage at the moment but I think it's a 15x8 on it (could be 16x7). Was 17x7-8 at 500kV. Way too large for a MoAss IMO as it made the tail very sluggish in comparison.
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Re: How to build an Epower system

PostPosted: Tue May 30, 2017 10:01 pm

Thanks Mike. Looks like I need a 530KV with a 15X8 :tu:
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Re: How to build an Epower system

PostPosted: Sun Jul 02, 2017 1:25 pm

Easy order on the 4315 530 :tu: :tu: Ken has 530KV as an option right on the website :tu: :tu:
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Re: How to build an Epower system

PostPosted: Mon Jul 03, 2017 7:18 am

Is that gonna be ready for testing this weekend? Im in need of another 4315 myself and still not sure what kv I want.
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Re: How to build an Epower system

PostPosted: Mon Jul 03, 2017 11:33 pm

steener wrote:Is that gonna be ready for testing this weekend? Im in need of another 4315 myself and still not sure what kv I want.


:lol: :lol: Only just ordered. No testing for quite some time..
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Re: How to build an Epower system

PostPosted: Sun Jul 16, 2017 3:22 pm

Number testing from Ottumwa ProBro with Steener and TriFlyer:

Props were all wood Xoar or similar.

Motrolfly 4315 500 KV:
15X8 E Prop – 1284 Watts / 57 Amps
15X7 E Prop – 1203 Watts / 50 Amps
16X6 Glow Prop – 1424 Watts / 66 Amps
AXI 4120/18 500 KV:
15X7 E Prop – 1388 Watts / 63 Amps
16X6 Glow Prop – 1273 Watts / 56 Amps
** Something Errored out on that test as the 16” AXI Numbers don’t
add up
Turnigy SK 5055 580 KV:
15X6 Glow Prop – 1787 Watts / 82 Amps
16X6 Glow Prop – 2194 Watts / 103 Amps
** Batteries were down 80% after testing.
** This is on a 5LB plane, Rons new HotStix.
15X6 = 357 watts / lb
16X6 = 439 watts / lb

Hopefully TriFlyer and Steener will comment, but here's what I got from this testing. The 15" props on the 500 KV Motrolfly aren't even making it break a sweat. 16" is the way to go, and also Cartman came along and noted that he runs 16 inch props on all his 500KV setups. I have the 530KV Motrolfly and will have it ready for the GreenBay Probro.
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Re: How to build an Epower system

PostPosted: Sun Jul 16, 2017 4:21 pm

What bats were used?

A 16x7 is pretty much the prop for a true 500 kv motor, or 15x8 if more speed is your thing.
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